SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ab3983df9accab14f694b50afcad7e5be1576429ed24e0b098a8e40819eea10' 
  AND token = 'Z07bNgutsE6eGulwEZyBRiqF0vJgxwCX684rgymzgl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}